What is selective attention, and which classic experimental paradigm is most associated with studying it?

A: The ability to attend to all stimuli simultaneously — studied via the Stroop task

B: The ability to focus on one stimulus while filtering out others — studied via dichotic listening tasks

C: The tendency to notice changes in a visual scene — studied via the flicker paradigm

D: The capacity to divide attention equally between two tasks — studied via dual-task experiments

Correct: The ability to focus on one stimulus while filtering out others — studied via dichotic listening tasks

Selective attention refers to the cognitive process of focusing on a particular stimulus while ignoring competing inputs. Cherry (1953) developed the dichotic listening paradigm — where different messages are played into each ear and participants shadow one — revealing that unattended information is largely filtered out but that personally relevant cues (like one's own name) can break through. This "cocktail party effect" demonstrates that attention operates at a semantic level.

Inattentional blindness demonstrates that we can fail to notice a clearly visible and unexpected object when our attention is focused elsewhere.

Answer: True

Inattentional blindness was famously demonstrated by Simons & Chabris (1999) in the "invisible gorilla" study: participants counting basketball passes failed to notice a person in a gorilla suit walking through the scene. This shows that conscious awareness depends not just on sensory input but on attentional allocation — even salient stimuli can be missed when attention is engaged elsewhere.

What is the difference between bottom-up and top-down perceptual processing?

A: Bottom-up is fast; top-down is slow

B: Bottom-up is driven by stimulus features in the environment; top-down is guided by prior knowledge, expectations, and goals

C: Bottom-up processes occur in the cortex; top-down processes occur in subcortical structures

D: Bottom-up processing requires attention; top-down processing is automatic

Correct: Bottom-up is driven by stimulus features in the environment; top-down is guided by prior knowledge, expectations, and goals

Bottom-up (data-driven) processing starts from raw sensory input — features are extracted and assembled into percepts without prior knowledge influencing the process. Top-down (conceptually driven) processing uses expectations, context, memory, and goals to shape perception — explaining why we can recognise degraded images, read poor handwriting, or hear spoken words in noise. Most real-world perception involves both simultaneously.

Change blindness refers to which phenomenon?

A: The inability to perceive motion in a stationary image

B: The surprising failure to detect large changes to a visual scene, especially during eye movements or brief interruptions

C: The adaptation of colour perception after prolonged exposure to a hue

D: The difficulty distinguishing similar colours under low illumination

Correct: The surprising failure to detect large changes to a visual scene, especially during eye movements or brief interruptions

Change blindness is the failure to notice substantial changes to a visual scene when those changes are introduced during a saccade (rapid eye movement), a brief blank screen, an occlusion, or even in plain view. Rensink et al. (1997) showed that changes to objects of central interest were noticed faster than peripheral ones, implicating attention in change detection. Change blindness contradicts the intuition that we maintain a detailed internal representation of our visual world.

Match each attentional phenomenon to its definition.

The Stroop task demonstrates that automatic processes can interfere with controlled, intentional behaviour.

Answer: True

In the Stroop task (Stroop, 1935), participants name the ink colour of colour words (e.g., the word "RED" written in blue ink). Reading the word is highly automated and interferes with the intentional task of naming the colour, producing slower and more error-prone responses. The Stroop effect is a reliable measure of executive function and cognitive control — the ability to override automatic responses — and is widely used in neuropsychological assessment.

Which brain region is most critically associated with top-down attentional control?

A: Primary visual cortex (V1)

B: Cerebellum

C: Prefrontal and parietal cortices (the frontoparietal network)

D: Basal ganglia

Correct: Prefrontal and parietal cortices (the frontoparietal network)

Top-down attentional control is mediated by a frontoparietal network centred on the dorsolateral prefrontal cortex (dlPFC) and posterior parietal cortex (PPC). This network exerts "goal-directed" attentional biases on visual processing areas. In contrast, the ventral frontoparietal network (including the temporoparietal junction) is responsible for stimulus-driven, bottom-up attentional capture — the "circuit-breaker" activated by unexpected salient events.